1. Field of the Invention
This invention relates to the field of rotary heat exchangers and more particularly to the use of such heat exchangers in a domestic clothes dryer.
2. Description of the Prior Art
Rotary regenerative heat exchangers, or rotary regenerators, typically comprise an annular matrix in the form of a wheel. The matrix is rotated into continuous consecutive contact with relatively hot and cold gas flows so that heat given up to the matrix by the hot flow can be transferred from the matrix to the cold flow. To obtain good heat transfer by the matrix, it has been generally thought that materials having high molecular density or mass, such as metallic wool, should be used for the matrix and that the wheel should revolve relatively slowly, such as about 100 rpm, in the regenerator. The high mass associated with these prior art regenerators requires that they be, in many cases, quite bulky; and the low drive speeds frequently necessitate cumbersome speed reducing mechanisms.
The heavy equipment and space considerations connected with these prior art rotary heat exchangers makes their use in domestic clothes dryers generally unacceptable. Nevertheless, it is well known that dryer apparatus may be more efficiently operated by affording heat exchange between exhaust air of the dryer and fresh intake air.